What is the management of a mild allergic reaction to medication?

From the Guidelines

For managing a mild allergic reaction to medication, I recommend immediately stopping the medication and taking an antihistamine like diphenhydramine (Benadryl) 25-50mg every 4-6 hours or cetirizine (Zyrtec) 10mg once daily, as suggested by the guidelines for the diagnosis and management of food allergy in the United States 1.

Key Considerations

• Apply a cold compress to reduce itching and swelling, and use calamine lotion or 1% hydrocortisone cream on affected skin areas.
• Stay hydrated and monitor symptoms closely, as mild allergic reactions can progress to more severe symptoms like anaphylaxis.
• If you experience difficulty breathing, facial swelling, or other severe symptoms, seek emergency medical attention immediately, as this indicates anaphylaxis.
• For future reference, document this allergic reaction and inform all healthcare providers about this medication allergy.

Mechanism of Allergic Reactions

Mild allergic reactions occur when your immune system overreacts to a medication, releasing histamine and other chemicals that cause symptoms like rash, hives, or itching. While antihistamines block these chemicals to reduce symptoms, complete avoidance of the triggering medication is essential to prevent potentially more serious reactions in the future, as medications can cause anaphylactic reactions due to the development of drug-specific IgE antibodies during a preceding period of sensitization 1.

Monitoring and Follow-up

Ongoing observation and monitoring are warranted to ensure a lack of progression to more significant symptoms of anaphylaxis, and if progression or increased severity is noted, epinephrine should be administered immediately, especially if there is a history of a prior severe allergic reaction 1.

From the FDA Drug Label

1 INDICATIONS & USAGE Adrenalin® is available as a single-use 1 mL vial and a multiple-use 30 mL vial for intramuscular and subcutaneous use. Emergency treatment of allergic reactions (Type I), including anaphylaxis, which may result from allergic reactions to insect stings, biting insects, foods, drugs, sera, diagnostic testing substances and other allergens, as well as idiopathic anaphylaxis or exercise-induced anaphylaxis.

2 DOSAGE & ADMINISTRATION Inject Adrenalin® intramuscularly or subcutaneously into the anterolateral aspect of the thigh, through clothing if necessary. When administering to a child, to minimize the risk of injection related injury, hold the leg firmly in place and limit movement prior to and during an injection. The injection may be repeated every 5 to 10 minutes as necessary For intramuscular administration, use a needle long enough (at least 1/2 inch to 5/8 inch) to ensure the injection is administered into the muscle. Monitor the patient clinically for the severity of the allergic reaction and potential cardiac effects of the drug, with repeat doses titrated to effect

The management of mild allergic reactions from medication involves administering epinephrine (IM). The dosage for adults and children 30 kg (66 lbs) or more is 0.3 to 0.5 mg (0.3 mL to 0.5 mL) of undiluted Adrenalin® administered intramuscularly or subcutaneously in the anterolateral aspect of the thigh, up to a maximum of 0.5 mg (0.5 mL) per injection, repeated every 5 to 10 minutes as necessary 2. For children less than 30 kg (66 lbs), the dosage is 0.01 mg/kg (0.01 mL/kg) of undiluted Adrenalin® administered intramuscularly or subcutaneously in the anterolateral aspect of the thigh, up to a maximum of 0.3 mg (0.3 mL) per injection, repeated every 5 to 10 minutes as necessary 2.

• Key considerations:
  • Administer epinephrine intramuscularly or subcutaneously into the anterolateral aspect of the thigh.
  • Monitor the patient clinically for the severity of the allergic reaction and potential cardiac effects of the drug.
  • Repeat doses titrated to effect, with injections repeated every 5 to 10 minutes as necessary 2.
  • Epinephrine is used for emergency treatment of allergic reactions (Type I), including anaphylaxis 2.

From the Research

Mild Allergic Reaction from Medication Management

• A mild allergic reaction from medication management can manifest as urticaria and swelling, and can be caused by various medications 3.
• Symptoms of an allergic reaction can range from mild to severe, including abdominal cramping and respiratory collapse, with anaphylaxis and anaphylactic shock being the most severe forms 3.
• Glucocorticoids, which are frequently used to treat allergic reactions, can also induce allergic reactions, including anaphylaxis 4.
• Hypersensitivity reactions to corticosteroids are rare, but can occur, and are broadly divided into immediate and non-immediate reactions 5.
• The management of drug allergy involves identifying and managing the signs and symptoms of an allergic reaction, and using tests to diagnose drug allergy 6.
• The use of epinephrine, antihistamines, and corticosteroids in the management of anaphylaxis has been studied, with epinephrine being the first-line treatment, and antihistamines and corticosteroids being used as adjunctive therapies 7.

Treatment Options

• Epinephrine is the primary treatment for anaphylaxis, and its early use can reduce the risk of uncontrolled reactions and hospital admission 7.
• Antihistamines may also be beneficial in the management of anaphylaxis, reducing the risk of uncontrolled reactions and hospital admission 7.
• Corticosteroids, however, may not be as effective in the management of anaphylaxis, and their use should be revisited 7.
• Careful challenge testing is necessary to select glucocorticoids that are safe for future treatment in patients who have experienced an allergic reaction to a glucocorticoid 4.
• A detailed evaluation is required to confirm the presence of a true hypersensitivity reaction to a suspected drug and to choose the safest alternative 5.